Ok, so I feel kind of bad...I have Batman in his 1 gallon still. ( longer than I wanted to keep him there) Cleo is in the 5 gallon for now. I have been checking out craigslist and thrift stores and I haven't been able to find a tank. At this point (because i'm low on funds) I am thinking I might just go buy a plain hoodless 10 gallon tank ($10.00). and make or find a divider, that way they can both have a nice amount of space.

I have a "can" type clip light, It can hold up to 150 watts. (not planning on using 150 watts!)

What wattage light should I use if I clip the light over the tank?
Do you think this will work ?

Wattage - I would go anywhere from 10 watts to 26 watts. If you have live plants use a 20+ watt bulb with 6500k. If not then just save money and use a 10-15 watt bulb. Make sure the bulbs are CFL not incandescents. Incandescent bulbs can cause temp fluctuations and waste alot of energy and dont make you fish look as good.

If you will be dividing without a hood, leave at least 4-5 inches from the top of the divider to the water level. I dont think any long finned bettas can jump that high.

You can also put mesh (the cheap plastic kind used for crochet- .50 at stores lol!) to cover the top part near your divider, so it over hangs and if they jump, they'd hit that, so long as it has like 2 inches of over hang. or you can even put a bunch together like [ ][ ][ ] and make your own top!

You can also put mesh (the cheap plastic kind used for crochet- .50 at stores lol!) to cover the top part near your divider, so it over hangs and if they jump, they'd hit that, so long as it has like 2 inches of over hang. or you can even put a bunch together like [ ][ ][ ] and make your own top!

That is an excellent idea! I wonder if I did the full top though if the light could get through ok?
Or screening? Like the plastic screening they use to make window screens?

Id say that's fine- but metal Idk- it might not do well when exposed to such intense light or water and may be rough! You can get that in plastic, too. If you wanted to keep the heat in, too, you could use that screen and then cover part of it up :D
Id say the light will be fine- The slats/squares in the plastic mesh can fit a penicl tip to like mid sharpened point :D

Bummer that you can't find anything at thrift stores mine always has evil bowls, but they did have a 20 long for $9.99! Which is now mine lol the guy said that fish tanks go pretty fast.I have yet to check it for leaks yet I was waiting for it to warm up so I could do it outside then I relized I could just use the bathtub lol so I am going to check it tomorrow.Goodluck splitting you tank I can't wait to see what it looks like.